The photos of Jeffrey Falk that have surfaced thus far are so blurry that they can't help but seem disturbing — particularly in light of the charges against him.

Falk, a 51-year-old former math teacher who was on the staff at ThunderRidge High School for nineteen years, has been accused of crimes related to child pornography, stalking and more.

The grades for Falk on RateMyTeacher.com are mostly positive, but with a few caveats. Here are some examples:

This guy is a great teacher. He is super cool and very approachable. He really cares for students. I have even seen him get involved outside of the classroom. But he is a math teacher and math is hard.

He's very fun and easy going but will make you work hard. As long as it's not a test day he will help you.

Falk is the best. If you do your homework you'll do fine on the tests.

Falk is a hard teacher, but he teaches well. My only complaint is that he makes you feel stoopid when you ask a question.

Doesn't help you in a understandable matter. Thinks he is the best. Always punches, hits or flicks you!

Student safety is our top priority here at ThunderRidge High School and the Douglas County School District. For that reason, I want to let you know about an investigation regarding one of our former teachers, Jeff Falk.

We have learned that Mr. Falk has been arrested by the Douglas County Sheriff's Office on charges including Sexual Exploitation of a Child, Stalking and Computer Crime. Mr. Falk was a math teacher at TRHS from July 1995 to July 2014....

I can assure you that ThunderRidge High School and Douglas County School District take this matter extremely seriously and we are cooperating fully with law enforcement. Because this is an ongoing criminal investigation, the Sheriff's Office has asked that we not disclose further information on the case.

Please do not hesitate to contact me with any concerns or questions. If you have further information about the investigation, contact the Douglas County Sheriff’s Office or our School Resource Officer.

Thus far, neither the Douglas County Sheriff's Office nor the 18th Judicial District DA's office have shared details about the case against Falk beyond the charges for which he was arrested. The following are the allegations against him related to a case filed on September 21:

As of last night, Falk reportedly remained behind bars on a $600,000 bond. His next court hearing is scheduled for October 30. No mug shot of Falk has been released as of this writing.

In the meantime, the DCSO stresses that the investigation into Falk's activities is continuing. If you have any information that might interest law enforcement, you're encouraged to contact the sheriff's office tip line at 303-660-7579. Look below to see a Fox31 piece about the case.